Papers by Beatriz Cobo Martin
SPIE Proceedings, 2016
The X-ray Integral Field Unit (X-IFU) on board the Advanced Telescope for High-ENergy Astrophysic... more The X-ray Integral Field Unit (X-IFU) on board the Advanced Telescope for High-ENergy Astrophysics (Athena) will provide spatially resolved high-resolution X-ray spectroscopy from 0.2 to 12 keV, with ∼ 5" pixels over a field of view of 5 arc minute equivalent diameter and a spectral resolution of 2.5 eV up to 7 keV. In this paper, we first review the core scientific objectives of Athena, driving the main performance parameters of the X-IFU, namely the spectral resolution, the field of view, the effective area, the count rate capabilities, the instrumental background. We also illustrate the breakthrough potential of the X-IFU for some observatory science goals. Then we briefly describe the X-IFU design as defined at the time of the mission consolidation review concluded in May 2016, and report on its predicted performance. Finally, we discuss some options to improve the instrument performance while not increasing its complexity and resource demands (e.g. count rate capability, spectral resolution).
Site-specific simulation of clutter-limited radar systems
IEEE Antennas and Propagation Society Symposium, 2004., 2004
Abstract This paper presents a new simulator for predicting the performance of low-angle radars i... more Abstract This paper presents a new simulator for predicting the performance of low-angle radars involving the study of the limiting landsea clutter signal in the receiver. Physical Optics (PO) in conjunction with Digitized Terrain Elevation Data (DTED) allow the environment to be ...
Site-specific simulation of ship safety/surveillance radars operating in harbour environments
IEEE VTS 53rd Vehicular Technology Conference, Spring 2001. Proceedings (Cat. No.01CH37202), 2001
This paper presents a method to predict site-specific radar coverage. The method is based on solv... more This paper presents a method to predict site-specific radar coverage. The method is based on solving the monostatic scattering problem by using the physical optics (PO) or Kirchhoff method, in combination with the use of geographical information systems, to model the specific terrain. The possibility to calculate the radar coverage, the time of arrival of the reflected pulses and the
Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray, 2014
We are developing the digital readout electronics (DRE) of the X-Ray Integral Field Unit (X-IFU),... more We are developing the digital readout electronics (DRE) of the X-Ray Integral Field Unit (X-IFU), one of the two Athena focal plane instruments. This subsystem is made of two main parts: the DRE-DEMUX and the DRE-EP. With a frequency domain multiplexing (FDM) the DRE-DEMUX makes the readout of the 3 840 Transition Edge Sensors (TES) in 96 channels of 40 pixels each. It provides the AC signals to voltage-bias the TES, it demodulates the detector's data which are readout by a SQUID and low noise amplifiers and it linearizes the detection chain to increase its dynamic range. The feedback is computed with a specific technique, so called baseband feedback (BBFB) which ensures that the loop is stable even with long propagation and processing delays (i.e. a few µs) and with high frequency AC-bias (up to 5 MHz). This processing is partly analogue (anti aliasing and reconstruction filters) but mostly digital. The digital firmware is simultaneously applied to all the pixels in digital integrated circuits. After the demultiplexing the interface between the DRE-DEMUX and the DRE-EP has to cope with a data rate of 61.44 Gbps to transmit the data of the individual pixels. Then, the DRE-EP detects the events and computes their energy and grade according to their spectral quality: low resolution, medium resolution and high resolution (i.e. if two consecutive events are too close the estimate of the energy is less accurate). This processing is done in LEON based processor boards. At its output the DRE-EP provides the control unit of the instrument with a list including for each event its time of arrival, its energy, its location on the focal plane and its grade.
SPIE Proceedings, 2016
The X-ray Integral Field Unit (X-IFU) microcalorimeter, on-board Athena, with its focal plane com... more The X-ray Integral Field Unit (X-IFU) microcalorimeter, on-board Athena, with its focal plane comprising 3840 Transition Edge Sensors (TESs) operating at 90 mK, will provide unprecedented spectral-imaging capability in the 0.2-12 keV energy range. It will rely on the on-board digital processing of current pulses induced by the heat deposited in the TES absorber, as to recover the energy of each individual events. Assessing the capabilities of the pulse reconstruction is required to understand the overall scientific performance of the X-IFU, notably in terms of energy resolution degradation with both increasing energies and count rates. Using synthetic data streams generated by the X-IFU End-to-End simulator, we present here a comprehensive benchmark of various pulse reconstruction techniques, ranging from standard optimal filtering to more advanced algorithms based on noise covariance matrices. Beside deriving the spectral resolution achieved by the different algorithms, a first assessment of the computing power and ground calibration needs is presented. Overall, all methods show similar performances, with the reconstruction based on noise covariance matrices showing the best improvement with respect to the standard optimal filtering technique. Due to prohibitive calibration needs, this method might however not be applicable to the X-IFU and the best compromise currently appears to be the so-called resistance space analysis which also features very promising high count rate capabilities.
The Athena X-ray Integral Field Unit (X-IFU)
Space Telescopes and Instrumentation 2016: Ultraviolet to Gamma Ray, 2016
The DRE: the digital readout electronics for ATHENA X-IFU
Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray, 2014
ABSTRACT We are developing the digital readout electronics (DRE) of the X-Ray Integral Field Unit... more ABSTRACT We are developing the digital readout electronics (DRE) of the X-Ray Integral Field Unit (X-IFU), one of the two Athena focal plane instruments. This subsystem is made of two main parts: the DRE-DEMUX and the DRE-EP. With a frequency domain multiplexing (FDM) the DRE-DEMUX makes the readout of the 3 840 Transition Edge Sensors (TES) in 96 channels of 40 pixels each. It provides the AC signals to voltage-bias the TES, it demodulates the detector's data which are readout by a SQUID and low noise amplifiers and it linearizes the detection chain to increase its dynamic range. The feedback is computed with a specific technique, so called baseband feedback (BBFB) which ensures that the loop is stable even with long propagation and processing delays (i.e. a few μs) and with high frequency AC-bias (up to 5 MHz). This processing is partly analogue (anti aliasing and reconstruction filters) but mostly digital. The digital firmware is simultaneously applied to all the pixels in digital integrated circuits. After the demultiplexing the interface between the DRE-DEMUX and the DRE-EP has to cope with a data rate of 61.44 Gbps to transmit the data of the individual pixels. Then, the DRE-EP detects the events and computes their energy and grade according to their spectral quality: low resolution, medium resolution and high resolution (i.e. if two consecutive events are too close the estimate of the energy is less accurate). This processing is done in LEON based processor boards. At its output the DRE-EP provides the control unit of the instrument with a list including for each event its time of arrival, its energy, its location on the focal plane and its grade.
Wireless Personal Communications, 2006
This paper presents the measurement and statistical analysis of the temporal variations of the ra... more This paper presents the measurement and statistical analysis of the temporal variations of the radio channel defined by a fixed link at 3.5 GHz in suburban areas. The analysis provides the required information about the temporal stability of the channel, the probability of occurrence and depth of fades, the Doppler spectrum and, in general, the influence of the environment on the signal behaviour. In particular, the effect of fast traffic on a motorway in the neighbourhood of the receiver is investigated, obtaining some general conclusions particularly useful in wireless communication systems design.
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Papers by Beatriz Cobo Martin